trivial: Remove dead code

The following functions are unused by anything but tests, or are only
used in one place and don't merit being in a utils module:

- xhtml_escape
- check_isinstance

Remove or replace them.

Change-Id: I5a57a416cb0912ad42fe8cdd6cf264020bdf2652

nova/tests/unit/test_utils.py

@@ -170,14 +170,6 @@ class GenericUtilsTestCase(test.NoDBTestCase):
                 self.assertEqual(fake_execute.uid, 2)
             self.assertEqual(fake_execute.uid, os.getuid())
 
-    def test_xhtml_escape(self):
-        self.assertEqual('"foo"', utils.xhtml_escape('"foo"'))
-        self.assertEqual(''foo'', utils.xhtml_escape("'foo'"))
-        self.assertEqual('&', utils.xhtml_escape('&'))
-        self.assertEqual('>', utils.xhtml_escape('>'))
-        self.assertEqual('&lt;', utils.xhtml_escape('<'))
-        self.assertEqual('&lt;foo&gt;', utils.xhtml_escape('<foo>'))
-
     def test_get_shortened_ipv6(self):
         self.assertEqual("abcd:ef01:2345:6789:abcd:ef01:c0a8:fefe",
                          utils.get_shortened_ipv6(
@@ -247,21 +239,6 @@ class GenericUtilsTestCase(test.NoDBTestCase):
         cmd = utils.get_root_helper()
         self.assertEqual('sudo nova-rootwrap foo', cmd)
 
-    @mock.patch('nova.utils.RootwrapProcessHelper')
-    def test_get_root_helper_proc(self, mock_proc_helper):
-        self.flags(use_rootwrap_daemon=False)
-        self.flags(rootwrap_config="/path/to/conf")
-        utils._get_rootwrap_helper()
-        mock_proc_helper.assert_called_once_with()
-
-    @mock.patch('nova.utils.RootwrapDaemonHelper')
-    def test_get_root_helper_daemon(self, mock_daemon_helper):
-        conf_path = '/path/to/conf'
-        self.flags(use_rootwrap_daemon=True)
-        self.flags(rootwrap_config=conf_path)
-        utils._get_rootwrap_helper()
-        mock_daemon_helper.assert_called_once_with(conf_path)
-
     def test_use_sudo(self):
         self.flags(disable_rootwrap=True, group='workarounds')
         cmd = utils.get_root_helper()

nova/utils.py

@@ -35,7 +35,6 @@ import sys
 import tempfile
 import textwrap
 import time
-from xml.sax import saxutils
 
 import eventlet
 import netaddr
@@ -163,13 +162,6 @@ def get_root_helper():
     return cmd
 
 
-def _get_rootwrap_helper():
-    if CONF.use_rootwrap_daemon:
-        return RootwrapDaemonHelper(CONF.rootwrap_config)
-    else:
-        return RootwrapProcessHelper()
-
-
 class RootwrapProcessHelper(object):
     def trycmd(self, *cmd, **kwargs):
         kwargs['root_helper'] = get_root_helper()
@@ -330,11 +322,6 @@ DEFAULT_PASSWORD_SYMBOLS = ('23456789',  # Removed: 0,1
                             'abcdefghijkmnopqrstuvwxyz')  # Removed: l
 
 
-# ~5 bits per symbol
-EASIER_PASSWORD_SYMBOLS = ('23456789',  # Removed: 0, 1
-                           'ABCDEFGHJKLMNPQRSTUVWXYZ')  # Removed: I, O
-
-
 def last_completed_audit_period(unit=None, before=None):
     """This method gives you the most recently *completed* audit period.
 
@@ -480,13 +467,7 @@ def get_my_linklocal(interface):
         raise exception.NovaException(msg)
 
 
-def xhtml_escape(value):
-    """Escapes a string so it is valid within XML or XHTML.
-
-    """
-    return saxutils.escape(value, {'"': '"', "'": '''})
-
-
+# TODO(sfinucan): Replace this with the equivalent from oslo.utils
 def utf8(value):
     """Try to turn a string into utf-8 if possible.
 
@@ -503,13 +484,6 @@ def utf8(value):
     return value.encode('utf-8')
 
 
-def check_isinstance(obj, cls):
-    """Checks that obj is of type cls, and lets PyLint infer types."""
-    if isinstance(obj, cls):
-        return obj
-    raise Exception(_('Expected object of type: %s') % (str(cls)))
-
-
 def parse_server_string(server_str):
     """Parses the given server_string and returns a tuple of host and port.
     If it's not a combination of host part and port, the port element

nova/virt/driver.py

@@ -28,7 +28,6 @@ import six
 
 import nova.conf
 from nova.i18n import _, _LE, _LI
-from nova import utils
 from nova.virt import event as virtevent
 
 CONF = nova.conf.CONF
@@ -1624,10 +1623,16 @@ def load_compute_driver(virtapi, compute_driver=None):
         driver = importutils.import_object(
             'nova.virt.%s' % compute_driver,
             virtapi)
-        return utils.check_isinstance(driver, ComputeDriver)
+        if isinstance(driver, ComputeDriver):
+            return driver
+        raise ValueError()
     except ImportError:
         LOG.exception(_LE("Unable to load the virtualization driver"))
         sys.exit(1)
+    except ValueError:
+        LOG.exception("Compute driver '%s' from 'nova.virt' is not of type"
+                      "'%s'", compute_driver, str(ComputeDriver))
+        sys.exit(1)
 
 
 def is_xenapi():